An interposer is a die or integrated circuit (IC) used to interface routing between other dies, ICs or between a die or IC and a package substrate. An interposer may comprise wiring, through-vias, and pads. Additionally, an interposer may comprise active electronic devices or circuits. Conventional through-vias are vias that extend entirely through the semiconductor wafer or die, and are coupled to contacts on the front surface and the back surface of the wafer or die. Through-vias within silicon wafers or dies are called through-silicon-vias (TSVs).
Three-dimensional ICs may comprise a number of thinned dies stacked one upon another with inter-die connection comprising through-vias. The three-dimensional ICs are capable of high-density and high performance and can result in cost savings.
Sensors and other ICs comprising devices or circuits may be bonded onto interposers comprising through-vias to couple to nodes within the sensors and the active ICs. The nodes may be coupled to, for example, packaging substrates or other devices and circuits.
Conventional through-vias comprise holes, through the wafer or die, formed by etching into the wafer from the front surface of the wafer. The conventional through-vias are formed prior to forming wiring, devices or circuits on the front surface of the wafer, or, alternately, the conventional through-vias are formed after forming the wiring, devices or circuits on the front surface of the wafer, and comprise holes through the wiring, devices or circuits.